<?php

class Facade
{
    private $sub_a;
    private $sub_b;
    private $sub_c;

    public function __construct()
    {
        $this->sub_a = new SubSystemA();
        $this->sub_b = new SubSystemB();
        $this->sub_c = new SubSystemC();
    }

    public function doFirst()
    {
        $this->sub_a->doA();
        $this->sub_c->doC();
    }

    public function doSecond()
    {
        $this->sub_b->doB();
        $this->sub_c->doC();
    }
}